What is the solution to x2-3x-13 = 0?

Looks like a job for the quadratic formula. ( discriminant says two real roots )

X = - b (+/-) sqrt(b^2-4ac)/2a

a = 1
b= - 3
c = - 13

X = - (- 3) (+/-) sqrt[(-3)^2 - 4(1)(- 13)]/2(1)

X = 3 (+/-) sqrt(9 + 52)/2

X = 3 (+/-) sqrt(61)/2
------exact

X = ~ 5.41
X = ~ - 2.41